The invention relates to an eye model for use in ophthalmological measurements, with a simulation of at least one eye structure.
In a multitude of measuring methods with which properties of eyes are measured, electromagnetic radiation (for short in the following: light) is beamed onto and/or into the eye to be examined, and the radiation reflected back from the eye is detected and evaluated. In the radiation reflected back, the influence exerted on the light by the various elements of the eye is mirrored, for which reason by recording the radiation reflected back from the eye statements can be made about properties of the eye, for example about pathological changes. In a multitude of measuring techniques the radiation reflected back from the eye is recorded by means of a camera, in particular an electronic camera. An example of a camera-based system for examining the eye is the so-called Scheimpflug camera system, with which, in particular, the cornea and the crystal-line lens can be examined. As is known, Scheimpflug photography enables a sharp imaging of an object plane that is oblique in relation to the image plane of the camera system.
In ophthalmological Scheimpflug photography the eye is transilluminated in layer-like manner with a slit projector. In this process, light emerging from the eye as a result of scattering is photographed obliquely in relation to the optical axis of the incident light, cf. DE 299 13 602 U1. Light-section photographs generated in such a manner using the Scheimpflug technique frequently require checking by means of reference measurements. For the purpose of implementing these reference measurements, artificially simulated eye models can be called upon. In addition to use for comparison measurements or calibration measurements, such eye models, which simulate one or more eye structures, also find application in ophthalmological research and practice in connection with the development of new measuring techniques or instruments.
An exemplary eye model is known from U.S. Pat. No. 7,066,598 B2. The eye model therein exhibits, inter alia, simulations of the cornea and of the lens of a human eye. The simulations consist of an acrylic plastic that has been doped with scattering substances in order to imitate the scattering properties of the real prototypes.
However, it has been shown that the actual scattering behaviour of the eye can only be imitated inadequately in this way. This is associated with the fact that, although a doping of a plastic body simulating the cornea or the lens with pigments or other scattering substances has the result that a volume scattering of light takes place in the imitating body, the light is subject to multiple scattering at all scattering interfaces and scattering substances on which it impinges. The multiple scattering results in an expansion of the beam of scattered light, by reason of which interfaces and contours cannot be detected with the desired sharpness.